Vehicles, such as locomotives, may include a prime mover that is powered by a fuel source to generate mechanical energy. In one example, mechanical energy generated by the prime mover may be converted to electrical energy that is used to power traction motors and other components and systems of the vehicle. In some examples, the prime mover may be a combustion engine that is fueled by diesel, gasoline, or other liquid petroleum distillates. In other examples the engine may additionally or alternatively utilize a gaseous fuel, such as natural gas.
In light of its favorable energy content, natural gas may be used as a fuel source for an engine. However, many existing engines are typically configured with only a single, liquid (e.g., diesel) fuel supply, limiting the opportunities for operating engines with natural gas. One example approach for supplying gaseous fuel to a diesel engine includes admitting gaseous fuel via the intake runners on each cylinder head. However, such an approach may be costly and difficult to apply to existing engine architectures, even on a small scale. Without significant redesign, the modifications required to the cylinder head may compromise the integrity of the head casting and likely result in reduced durability.